114 BRITISH PALEOZOIC SPONGES. 



4. Astylospongia inciso-lobata, F. Roemer. Plate II, figs. 5, 5 a. 



1860. Astylospongia inciso-lobata, F. Roemer. Die silur. Fauna d. westl. 



Tenn.,p.ll,pl.i,figs. 3,3a. 

 1848. Spongia — — Leonh. u. Bronn's Jabrb., 



p. 685. 



1861. Astylospongia — — Die fossile Fauna von Sade- 



witz, p. 13, pi. ii, fig. 4. 

 1864. — — Salter. Quart. Journ. Geol. Soc, vol. xx, 



p. 239, Note. 

 1873. — geata, — M.S. Cat. Cambrian and Silur. 



Foss. Cambridge, p. 31. 

 1880. — inciso-lobata, F. Roemer. Letbsea pal., p. 310. 



Sponges depressed spherical in form, with shallow furrows extending down 

 the sides so as to form imperfect lobes. The canals open freely at the summit of 

 the Sponge. 



The only British example of this species, now preserved in the Museum of the 

 Geological Survey, Jermyn Street, is 16 mm. in height by 36 mm. in transverse 

 diameter. The summit is slightly convex, and the canal-apertures, about 1 mm. in 

 width, are irregularly disposed over it. Six shallow furrows, indicating as many 

 lobes, extend from near the summit to the base. The interior of the specimen is now a 

 solid mass of iron-pyrites, in which only traces of canals can be distinguished, and, 

 as the spicular structure is altogether obliterated, its true character is not 

 altogether free from doubt. The specimen was originally referred to A. inciso- 

 lobata by Mr. Salter, but subsequently, in the catalogue of the Cambrian and 

 Silurian fossils at Cambridge, he named it A. grata, MS., without, however, adding 

 any description. As from the condition of the specimen no other feature beyond 

 the outer form is available for comparison, it seems preferable to place it in the 

 present species, which is distinguished by similar lobate outlines. 



Distribution. — Ordovician : Caradoc Shale, Haverford-west, South Wales. It 

 also occurs in Silurian strata in West Tennessee, and in Glacial Drift at Sadewitz, 

 Lower Silesia (F. Roemer.) 



